This invention relates to a process for the preparation of wort starting from mash, comprising the separation of spent grain from the mash. More in particular, the invention relates to a continuous process for the preparation of wort.
When making beverages from cereals, more in particular when brewing beer, wort is used. A conventional preparation of wort occurs by mixing the starting materials, e.g., comprising unmalted grain (for example maize). The solid materials are first crushed (pulverized) and then mixed with the water. The resulting suspension is kept for some time at a temperature of at least 40.degree. C. in the presence of an enzyme source, e.g., malt. Gelatinization and liquefaction thereby occur. In a next step the enzymatic conversion of the mixture (mash) is continued after supplementary addition of malt and/or an external enzyme source.
It is also possible to prepare wort on the basis of malt and water. Then the first step is omitted.
The product thus obtained consists mainly of water, insoluble components of the raw materials, as well as soluble components, such as fermentable and unfermentable sugars and proteins. In the conventional method this mixture is filtered to remove the insoluble components, the spent grain. The filtrate or extract is the wort. For brewing beer, hops are then added to the wort, which is boiled. The flakes formed, if any, are removed, and the wort is cooled to about 8.degree. C. and fermented.
European patent application 0 265 152 discloses the filtration of wort using a membrane having a pore diameter of from 10.0 to 100.0 .mu.m. As appears from the text of this publication, the membrane is intended to separate the spent grain from the mash, the advantage residing in that a smaller particle size of the starting products can thus be used. This has advantages relative to the extraction efficiency of the sugars from the raw materials.
The membrane filtration according to this publication does not result in a clear wort which is suitable for further use. In particular, it appears from the text of the application that the wort as initially produced is not free from suspended particles, so that a supplementary filtration is required. This is a drawback of this method. Moreover, the process as described in this publication cannot be carried out continuously.
The object of this invention is to provide a process for the preparation of wort starting from mash, the separation of the spent grain from the mash to form a clear wort, which process has the advantage that it can be carried out continuously, while furthermore the separation takes place at a higher yield of extract.